The present invention relates generally to hearing protective devices, and more particularly to hearing protective devices including a semi-rigid component.
The use of hearing protective and noise attenuating devices are well known, and various types of devices are available for this purpose. Such devices include, but are not limited to, earplugs and semi-aural devices. Foam components are well known for use with these devices, providing both sound attenuation and enhanced comfort for the wearer.
Earplugs are generally preferred for continuous use over longer periods of time. Foam earplugs composed of resilient polymer foam materials such as foam rubber or polyurethane are well known in the art. Slow recovery foam earplugs, such as those disclosed in U.S. Reissue. No. 29,487 to Gardner, Jr., are not only comfortable, but have also been shown to deliver high in-field noise protection at all frequencies. U.S. Pat. No. 5,203,352 to Gardner, Jr. also discloses a hearing protective earplug comprising a polymeric foam.
A hearing protective device may further include a cord that is attached to a pair of earplugs and extends therebetween. Conventional cords are commonly designed so that the cord may be permanently attached to the earplugs and more specifically, each end of the cord may be permanently attached to stem portions of the respective earplugs.
A typical semi-aural hearing protector assembly generally includes a resilient U-shaped band with holders at opposite ends, and a pair of inwardly directed ear protectors (“pods”) that are detachably mounted to the holders. Semi-aural hearing protectors that enter the ear canal offer hearing protection but are somewhat less comfortable than those that simply cap the ear. U.S. Pat. No. 4,461,290 to Gardner, Jr. et al. discloses a semi-aural device incorporating a foam component. U.S. Pat. No. 4,671,265 to Anderson also discloses a semi-aural device.
With respect to these devices, the sound-attenuating (acoustical) component has been made both of flexible, rubber-like materials, and of foam. For earplugs and semi-aural devices, the rubber-like materials are advantageous because they allow the earplug or device to be directly inserted into the wearer's ear. However, such earplugs and devices typically become uncomfortable over long periods of use. Foam earplugs provide enhanced comfort, but may require rolling down before insertion.
A foam earplug with a stem can provide both the ease of insertion of rubber-like earplugs and the comfort of foam earplugs. A number of patents disclose earplugs having tips or flanges with a relatively stiff stem used to insert and remove the earplug. One earplug, shown in Prior Art FIG. 1, is described in U.S. Pat. No. 5,188,123 to Gardner, herein incorporated by reference. This earplug includes a circular or ovoid resilient polymeric foam body having a rounded nose end. An elongated stem is axially embedded in the foam body and extends rearward and axially therefrom. The earplug may be used in a push-in or roll-down insertion mode.
While suitable for certain purposes, this prior art earplug requires an additional manufacturing step over conventional plugs to secure the stem in the foam body. Also, the material of the foam body is prone to peel from the insert. In addition, inclusion of a hard stem in the earplug could be a hazard for the user, the general concern being that potential injury could result should the hearing protector become impacted. On the other hand, if the stem is too soft, it tends to buckle upon insertion, limiting the fit of the earplug and reducing the potential usefulness of the stem.
Another attempted solution to the above-discussed deficiencies in the art is the use of a porous component as a stem as disclosed in U.S. Pat. No. 5,799,658 to Falco. Therein, individual porous stems are mechanically bonded to the foam during manufacture by controlled penetration of the foam by the porous component stem. However, the individual porous stems are relatively expensive and somewhat difficult to manufacture.
Accordingly, there remains a need for a stemmed foam earplug that is effective in providing hearing protection, yet convenient and comfortable to use, and has a more efficient and lower cost method of manufacture.